Re: Steam . can we back-up a game on CD?

Are we allowed to make a back-up copy
on CD for our own use?
and if so, how?

Sort of. Check ***here***.

I guess what I was saying was
can I transfer the game to a DVD/CD?
And if so how?
{would CD/DVD be better copy?}

As far as I can tell from that webpage, you can back the game up on DVD (I doubt most games would fit on a CD). However it isn't as simple as burning the game's installer file(s) to a DVD. And you probably need internet connectivity when you restore to another computer or reformatted hard drive from the back up in order to "activate." What you don't have to do is re-download the bulk of the game, which may be several gigabytes in size. And you have to back up saves, etc. separately.